[Switch Access] Create settings page

This commit creates a settings page for Switch Access behind the
Switch Access experimental flag. The page is not accessible to users at
this point except by typing in the direct URL
(chrome://settings/manageAccessibility/switchAccess) with the flag
enabled. The preferences set here are not yet connected to the behavior
of Switch Access.

Bug: 958081
Change-Id: I86951e2877c18c047053a4ec3fcb3b2f18dd46b5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1600082
Commit-Queue: Anastasia Helfinstein <anastasi@google.com>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Dan Beam <dbeam@chromium.org>
Reviewed-by: Katie Dektar <katie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#665705}

ash/accessibility/accessibility_controller.cc

@@ -18,6 +18,7 @@
 #include "ash/keyboard/ash_keyboard_controller.h"
 #include "ash/keyboard/ui/keyboard_util.h"
 #include "ash/policy/policy_recommendation_restorer.h"
+#include "ash/public/cpp/ash_constants.h"
 #include "ash/public/cpp/ash_pref_names.h"
 #include "ash/public/cpp/notification_utils.h"
 #include "ash/public/cpp/shell_window_ids.h"
@@ -300,6 +301,26 @@ void AccessibilityController::RegisterProfilePrefs(PrefRegistrySimple* registry,
                                   false);
     registry->RegisterBooleanPref(prefs::kAccessibilitySwitchAccessEnabled,
                                   false);
+    registry->RegisterListPref(prefs::kAccessibilitySwitchAccessSelectKeyCodes,
+                               base::Value(std::vector<base::Value>()));
+    registry->RegisterIntegerPref(
+        prefs::kAccessibilitySwitchAccessSelectSetting,
+        kSwitchAccessAssignmentNone);
+    registry->RegisterListPref(prefs::kAccessibilitySwitchAccessNextKeyCodes,
+                               base::Value(std::vector<base::Value>()));
+    registry->RegisterIntegerPref(prefs::kAccessibilitySwitchAccessNextSetting,
+                                  kSwitchAccessAssignmentNone);
+    registry->RegisterListPref(
+        prefs::kAccessibilitySwitchAccessPreviousKeyCodes,
+        base::Value(std::vector<base::Value>()));
+    registry->RegisterIntegerPref(
+        prefs::kAccessibilitySwitchAccessPreviousSetting,
+        kSwitchAccessAssignmentNone);
+    registry->RegisterBooleanPref(
+        prefs::kAccessibilitySwitchAccessAutoScanEnabled, false);
+    registry->RegisterIntegerPref(
+        prefs::kAccessibilitySwitchAccessAutoScanSpeedMs,
+        kDefaultSwitchAccessAutoScanSpeed.InMilliseconds());
     registry->RegisterBooleanPref(prefs::kAccessibilityVirtualKeyboardEnabled,
                                   false);
     registry->RegisterBooleanPref(

ash/public/cpp/ash_constants.h

@@ -37,6 +37,15 @@ constexpr int kFocusBorderThickness = 2;
 
 constexpr int kDefaultLargeCursorSize = 64;
 
+// The option in the Switch Access settings for no switch assigned.
+constexpr int kSwitchAccessAssignmentNone = 0;
+
+// The default delay before Switch Access automatically moves to the next
+// element on the page that is interesting, based on the Switch Access
+// predicates.
+constexpr base::TimeDelta kDefaultSwitchAccessAutoScanSpeed =
+    base::TimeDelta::FromMilliseconds(1200);
+
 // The default wait time between last mouse movement and sending autoclick.
 constexpr int kDefaultAutoclickDelayMs = 1000;
 

ash/public/cpp/ash_pref_names.cc

@@ -81,7 +81,34 @@ const char kAccessibilityFocusHighlightEnabled[] =
 const char kAccessibilitySelectToSpeakEnabled[] =
     "settings.a11y.select_to_speak";
 // A boolean pref which determines whether switch access is enabled.
-const char kAccessibilitySwitchAccessEnabled[] = "settings.a11y.switch_access";
+const char kAccessibilitySwitchAccessEnabled[] =
+    "settings.a11y.switch_access.enabled";
+// A pref that stores the key code for the "select" action.
+const char kAccessibilitySwitchAccessSelectKeyCodes[] =
+    "settings.a11y.switch_access.select.key_codes";
+// A pref that stores the setting value for the "select" action.
+const char kAccessibilitySwitchAccessSelectSetting[] =
+    "settings.a11y.switch_access.select.setting";
+// A pref that stores the key code for the "next" action.
+const char kAccessibilitySwitchAccessNextKeyCodes[] =
+    "settings.a11y.switch_access.next.key_codes";
+// A pref that stores the setting value for the "next" action.
+const char kAccessibilitySwitchAccessNextSetting[] =
+    "settings.a11y.switch_access.next.setting";
+// A pref that stores the key code for the "previous" action.
+const char kAccessibilitySwitchAccessPreviousKeyCodes[] =
+    "settings.a11y.switch_access.previous.key_codes";
+// A pref that stores the setting value for the "previous" action.
+const char kAccessibilitySwitchAccessPreviousSetting[] =
+    "settings.a11y.switch_access.previous.setting";
+// A boolean pref which determines whether auto-scanning is enabled within
+// switch access.
+const char kAccessibilitySwitchAccessAutoScanEnabled[] =
+    "settings.a11y.switch_access.auto_scan.enabled";
+// An integer pref which determines time delay in ms before automatically
+// scanning forward (when auto-scan is enabled).
+const char kAccessibilitySwitchAccessAutoScanSpeedMs[] =
+    "settings.a11y.switch_access.auto_scan.speed_ms";
 // A boolean pref which determines whether dictation is enabled.
 const char kAccessibilityDictationEnabled[] = "settings.a11y.dictation";
 // A boolean pref which determines whether the accessibility menu shows

ash/public/cpp/ash_pref_names.h

@@ -33,6 +33,15 @@ ASH_PUBLIC_EXPORT extern const char kAccessibilityCursorHighlightEnabled[];
 ASH_PUBLIC_EXPORT extern const char kAccessibilityFocusHighlightEnabled[];
 ASH_PUBLIC_EXPORT extern const char kAccessibilitySelectToSpeakEnabled[];
 ASH_PUBLIC_EXPORT extern const char kAccessibilitySwitchAccessEnabled[];
+ASH_PUBLIC_EXPORT extern const char kAccessibilitySwitchAccessSelectKeyCodes[];
+ASH_PUBLIC_EXPORT extern const char kAccessibilitySwitchAccessSelectSetting[];
+ASH_PUBLIC_EXPORT extern const char kAccessibilitySwitchAccessNextKeyCodes[];
+ASH_PUBLIC_EXPORT extern const char kAccessibilitySwitchAccessNextSetting[];
+ASH_PUBLIC_EXPORT extern const char
+    kAccessibilitySwitchAccessPreviousKeyCodes[];
+ASH_PUBLIC_EXPORT extern const char kAccessibilitySwitchAccessPreviousSetting[];
+ASH_PUBLIC_EXPORT extern const char kAccessibilitySwitchAccessAutoScanEnabled[];
+ASH_PUBLIC_EXPORT extern const char kAccessibilitySwitchAccessAutoScanSpeedMs[];
 ASH_PUBLIC_EXPORT extern const char kAccessibilityDictationEnabled[];
 ASH_PUBLIC_EXPORT extern const char kShouldAlwaysShowAccessibilityMenu[];
 

chrome/app/settings_strings.grdp

@@ -190,6 +190,42 @@
     <message name="IDS_SETTINGS_TTS_LINK_DESCRIPTION" desc="Description of link to manage text-to-speech settings">
       Select and customize text-to-speech voices
     </message>
+    <message name="IDS_SETTINGS_MANAGE_SWITCH_ACCESS_SETTINGS" desc="Title of the page to manage Switch Access settings.">
+      Switch Access settings
+    </message>
+    <message name="IDS_SETTINGS_SWITCH_ASSIGNMENT_HEADING" desc="Heading for the settings section for Switch Access to assign switches to actions">
+      Switch action assignment
+    </message>
+    <message name="IDS_SETTINGS_SWITCH_ASSIGN_OPTION_SPACE" desc="Label for the option to assign the spacebar as a switch.">
+      Space
+    </message>
+    <message name="IDS_SETTINGS_SWITCH_ASSIGN_OPTION_ENTER" desc="Label for the option to assign the enter key as a switch.">
+      Enter
+    </message>
+    <message name="IDS_SETTINGS_SWITCH_ASSIGN_OPTION_NONE" desc="Label for the option to have no switch assigned to an action.">
+      None
+    </message>
+    <message name="IDS_SETTINGS_ASSIGN_SELECT_SWITCH_LABEL" desc="Label for the setting to assign a switch to the action 'Select', which selects the currently focused element and begins an interaction (which varies depending on the element/other settings).">
+      Select
+    </message>
+    <message name="IDS_SETTINGS_ASSIGN_NEXT_SWITCH_LABEL" desc="Label for the setting to assign a switch to the action 'Next', which moves focus to the next element.">
+      Next
+    </message>
+    <message name="IDS_SETTINGS_ASSIGN_PREVIOUS_SWITCH_LABEL" desc="Label for the setting to assign a switch to the action 'Previous', which moves focus to the previous element.">
+      Previous
+    </message>
+    <message name="IDS_SETTINGS_SWITCH_ACCESS_AUTO_SCAN_HEADING" desc="Heading for the settings section containing preferences around Switch Access automatically scanning between elements.">
+      Auto-scan
+    </message>
+    <message name="IDS_SETTINGS_SWITCH_ACCESS_AUTO_SCAN_LABEL" desc="Label for the toggle which enables automatic scanning between elements in Switch Access.">
+      Enable auto-scan
+    </message>
+    <message name="IDS_SETTINGS_SWITCH_ACCESS_AUTO_SCAN_SPEED_LABEL" desc="Label for slider which sets the time interval for automatically scanning to the next element. Will be immediately followed by the numeric value of the interval.">
+      Scanning speed: <ph name="SPEED_WITH_UNITS">$1<ex>1.5s</ex></ph>
+    </message>
+    <message name="IDS_SETTINGS_DURATION_IN_SECONDS" desc="A duration in seconds. Should be short.">
+      <ph name="DURATION">$1<ex>1.5</ex></ph>s
+    </message>
     <message name="IDS_SETTINGS_LARGE_MOUSE_CURSOR_LABEL" desc="Label for checkbox which enables showing a larger mouse cursor than normal.">
       Show large mouse cursor
     </message>

chrome/browser/chromeos/preferences.cc

@@ -333,6 +333,37 @@ void Preferences::RegisterProfilePrefs(
   registry->RegisterBooleanPref(
       ash::prefs::kAccessibilitySwitchAccessEnabled, false,
       user_prefs::PrefRegistrySyncable::SYNCABLE_PREF | PrefRegistry::PUBLIC);
+  registry->RegisterListPref(
+      ash::prefs::kAccessibilitySwitchAccessSelectKeyCodes,
+      base::Value(std::vector<base::Value>()),
+      user_prefs::PrefRegistrySyncable::SYNCABLE_PREF | PrefRegistry::PUBLIC);
+  registry->RegisterIntegerPref(
+      ash::prefs::kAccessibilitySwitchAccessSelectSetting,
+      ash::kSwitchAccessAssignmentNone,
+      user_prefs::PrefRegistrySyncable::SYNCABLE_PREF | PrefRegistry::PUBLIC);
+  registry->RegisterListPref(
+      ash::prefs::kAccessibilitySwitchAccessNextKeyCodes,
+      base::Value(std::vector<base::Value>()),
+      user_prefs::PrefRegistrySyncable::SYNCABLE_PREF | PrefRegistry::PUBLIC);
+  registry->RegisterIntegerPref(
+      ash::prefs::kAccessibilitySwitchAccessNextSetting,
+      ash::kSwitchAccessAssignmentNone,
+      user_prefs::PrefRegistrySyncable::SYNCABLE_PREF | PrefRegistry::PUBLIC);
+  registry->RegisterListPref(
+      ash::prefs::kAccessibilitySwitchAccessPreviousKeyCodes,
+      base::Value(std::vector<base::Value>()),
+      user_prefs::PrefRegistrySyncable::SYNCABLE_PREF | PrefRegistry::PUBLIC);
+  registry->RegisterIntegerPref(
+      ash::prefs::kAccessibilitySwitchAccessPreviousSetting,
+      ash::kSwitchAccessAssignmentNone,
+      user_prefs::PrefRegistrySyncable::SYNCABLE_PREF | PrefRegistry::PUBLIC);
+  registry->RegisterBooleanPref(
+      ash::prefs::kAccessibilitySwitchAccessAutoScanEnabled, false,
+      user_prefs::PrefRegistrySyncable::SYNCABLE_PREF | PrefRegistry::PUBLIC);
+  registry->RegisterIntegerPref(
+      ash::prefs::kAccessibilitySwitchAccessAutoScanSpeedMs,
+      ash::kDefaultSwitchAccessAutoScanSpeed.InMilliseconds(),
+      user_prefs::PrefRegistrySyncable::SYNCABLE_PREF | PrefRegistry::PUBLIC);
   registry->RegisterBooleanPref(
       ash::prefs::kShouldAlwaysShowAccessibilityMenu, false,
       user_prefs::PrefRegistrySyncable::SYNCABLE_PREF);

chrome/browser/extensions/api/settings_private/prefs_util.cc

@@ -355,6 +355,22 @@ const PrefsUtil::TypedPrefMap& PrefsUtil::GetWhitelistedKeys() {
       settings_api::PrefType::PREF_TYPE_BOOLEAN;
   (*s_whitelist)[ash::prefs::kAccessibilitySwitchAccessEnabled] =
       settings_api::PrefType::PREF_TYPE_BOOLEAN;
+  (*s_whitelist)[ash::prefs::kAccessibilitySwitchAccessSelectKeyCodes] =
+      settings_api::PrefType::PREF_TYPE_LIST;
+  (*s_whitelist)[ash::prefs::kAccessibilitySwitchAccessSelectSetting] =
+      settings_api::PrefType::PREF_TYPE_NUMBER;
+  (*s_whitelist)[ash::prefs::kAccessibilitySwitchAccessNextKeyCodes] =
+      settings_api::PrefType::PREF_TYPE_LIST;
+  (*s_whitelist)[ash::prefs::kAccessibilitySwitchAccessNextSetting] =
+      settings_api::PrefType::PREF_TYPE_NUMBER;
+  (*s_whitelist)[ash::prefs::kAccessibilitySwitchAccessPreviousKeyCodes] =
+      settings_api::PrefType::PREF_TYPE_LIST;
+  (*s_whitelist)[ash::prefs::kAccessibilitySwitchAccessPreviousSetting] =
+      settings_api::PrefType::PREF_TYPE_NUMBER;
+  (*s_whitelist)[ash::prefs::kAccessibilitySwitchAccessAutoScanEnabled] =
+      settings_api::PrefType::PREF_TYPE_BOOLEAN;
+  (*s_whitelist)[ash::prefs::kAccessibilitySwitchAccessAutoScanSpeedMs] =
+      settings_api::PrefType::PREF_TYPE_NUMBER;
   (*s_whitelist)[ash::prefs::kAccessibilityVirtualKeyboardEnabled] =
       settings_api::PrefType::PREF_TYPE_BOOLEAN;
   (*s_whitelist)[ash::prefs::kAccessibilityMonoAudioEnabled] =

chrome/browser/prefs/pref_service_incognito_whitelist.cc

@@ -54,6 +54,14 @@ const char* const kPersistentPrefNames[] = {
     ash::prefs::kAccessibilityFocusHighlightEnabled,
     ash::prefs::kAccessibilitySelectToSpeakEnabled,
     ash::prefs::kAccessibilitySwitchAccessEnabled,
+    ash::prefs::kAccessibilitySwitchAccessSelectKeyCodes,
+    ash::prefs::kAccessibilitySwitchAccessSelectSetting,
+    ash::prefs::kAccessibilitySwitchAccessNextKeyCodes,
+    ash::prefs::kAccessibilitySwitchAccessNextSetting,
+    ash::prefs::kAccessibilitySwitchAccessPreviousKeyCodes,
+    ash::prefs::kAccessibilitySwitchAccessPreviousSetting,
+    ash::prefs::kAccessibilitySwitchAccessAutoScanEnabled,
+    ash::prefs::kAccessibilitySwitchAccessAutoScanSpeedMs,
     ash::prefs::kAccessibilityDictationEnabled,
     ash::prefs::kDockedMagnifierEnabled,
     ash::prefs::kDockedMagnifierScale,

chrome/browser/resources/settings/a11y_page/BUILD.gn

@@ -13,6 +13,7 @@ js_type_check("closure_compile") {
     deps += [
       ":externs",
       ":manage_a11y_page",
+      ":switch_access_subpage",
       ":tts_subpage",
     ]
   }
@@ -36,6 +37,15 @@ js_library("manage_a11y_page") {
   externs_list = [ "$externs_path/settings_private.js" ]
 }
 
+js_library("switch_access_subpage") {
+  deps = [
+    "..:route",
+    "//ui/webui/resources/js:i18n_behavior",
+    "//ui/webui/resources/js:load_time_data",
+    "//ui/webui/resources/js:web_ui_listener_behavior",
+  ]
+}
+
 js_library("tts_subpage") {
   deps = [
     ":externs",

chrome/browser/resources/settings/a11y_page/a11y_page.html

@@ -10,6 +10,7 @@
 <link rel="import" href="../controls/settings_toggle_button.html">
 <link rel="import" href="../settings_page/settings_animated_pages.html">
 <link rel="import" href="../settings_page/settings_subpage.html">
+<link rel="import" href="switch_access_subpage.html">
 <link rel="import" href="tts_subpage.html">
 </if>
 
@@ -56,6 +57,15 @@
             </settings-tts-subpage>
           </settings-subpage>
         </template>
+        <template is="dom-if" if="[[showExperimentalSwitchAccess_]]">
+          <template is="dom-if" route-path="/manageAccessibility/switchAccess">
+            <settings-subpage associated-control="[[$$('#subpage-trigger')]]"
+                page-title="$i18n{manageSwitchAccessSettings}">
+              <settings-switch-access-subpage prefs="{{prefs.settings.a11y}}">
+              </settings-switch-access-subpage>
+            </settings-subpage>
+          </template>
+        </template>
       </settings-animated-pages>
     </template>
     <cr-link-row class="hr" label="$i18n{moreFeaturesLink}"

chrome/browser/resources/settings/a11y_page/a11y_page.js

@@ -65,6 +65,18 @@ Polymer({
         return loadTimeData.getBoolean('showExperimentalA11yFeatures');
       },
     },
+
+    /**
+     * Whether to show Switch Access.
+     * @private {boolean}
+     */
+    showExperimentalSwitchAccess_: {
+      type: Boolean,
+      value: function() {
+        return loadTimeData.getBoolean(
+            'showExperimentalAccessibilitySwitchAccess');
+      },
+    },
     // </if>
   },
 

chrome/browser/resources/settings/a11y_page/manage_a11y_page.html

@@ -133,10 +133,11 @@
     </settings-toggle-button>
     <template is="dom-if" if="[[showExperimentalSwitchAccess_]]">
       <settings-toggle-button
-          pref="{{prefs.settings.a11y.switch_access}}"
+          pref="{{prefs.settings.a11y.switch_access.enabled}}"
           label="$i18n{switchAccessLabel}">
       </settings-toggle-button>
-      <iron-collapse opened="[[prefs.settings.a11y.switch_access.value]]">
+      <iron-collapse
+          opened="[[prefs.settings.a11y.switch_access.enabled.value]]">
         <cr-link-row label="$i18n{switchAccessOptionsLabel}"
             on-click="onSwitchAccessSettingsTap_" embedded external>
         </cr-link-row>

chrome/browser/resources/settings/a11y_page/switch_access_subpage.html

+<link rel="import" href="chrome://resources/html/polymer.html">
+
+<link rel="import" href="chrome://resources/html/i18n_behavior.html">
+<link rel="import" href="chrome://resources/html/md_select_css.html">
+<link rel="import" href="../controls/settings_dropdown_menu.html">
+<link rel="import" href="../controls/settings_slider.html">
+<link rel="import" href="../controls/settings_toggle_button.html">
+<link rel="import" href="../i18n_setup.html">
+<link rel="import" href="../settings_shared_css.html">
+
+<dom-module id="settings-switch-access-subpage">
+  <template>
+    <style include="settings-shared md-select">
+      h2 {
+        padding-inline-start: var(--cr-section-padding);
+      }
+    </style>
+    <h2>$i18n{switchAssignmentHeading}</h2>
+    <div class="list-frame">
+      <div class="settings-box continuation list-item">
+        <div class="start sub-item">
+          $i18n{assignSelectSwitchLabel}
+        </div>
+        <settings-dropdown-menu label="$i18n{assignSelectSwitchLabel}"
+            pref="{{prefs.switch_access.select.dropdown}}"
+            menu-options="[[switchAssignOptions_]]"
+            on-settings-control-change="onSelectAssigned_">
+        </settings-dropdown-menu>
+      </div>
+      <div class="settings-box continuation list-item">
+        <div class="start sub-item">
+          $i18n{assignNextSwitchLabel}
+        </div>
+        <settings-dropdown-menu label="$i18n{assignNextSwitchLabel}"
+            pref="{{prefs.switch_access.next.dropdown}}"
+            menu-options="[[switchAssignOptions_]]"
+            on-settings-control-change="onNextAssigned_">
+        </settings-dropdown-menu>
+      </div>
+      <div class="settings-box continuation list-item">
+        <div class="start sub-item">
+          $i18n{assignPreviousSwitchLabel}
+        </div>
+        <settings-dropdown-menu label="$i18n{assignPreviousSwitchLabel}"
+            pref="{{prefs.switch_access.previous.dropdown}}"
+            menu-options="[[switchAssignOptions_]]"
+            on-settings-control-change="onPreviousAssigned_">
+        </settings-dropdown-menu>
+      </div>
+    </div>
+    <h2>$i18n{switchAccessAutoScanHeading}</h2>
+    <div class="list-frame">
+      <settings-toggle-button class="continuation list-item"
+          pref="{{prefs.switch_access.auto_scan.enabled}}"
+          label="$i18n{switchAccessAutoScanLabel}">
+      </settings-toggle-button>
+      <div class="settings-box continuation list-item"
+          hidden$="[[!prefs.switch_access.auto_scan.enabled.value]]">
+        <div class="start sub-item" id="scanSpeed">
+          [[getLabelForSpeedSlider_(prefs.switch_access.auto_scan.speed_ms.*)]]
+        </div>
+        <settings-slider id="scanSpeedSlider" aria-describedby="scanSpeed"
+            pref="{{prefs.switch_access.auto_scan.speed_ms}}"
+            ticks="[[autoScanSpeedValuesMs_]]"
+            min="[[minScanSpeedMs_]]"
+            max="[[maxScanSpeedMs_]]"
+            label-min="[[minScanSpeedLabelSec_]]"
+            label-max="[[maxScanSpeedLabelSec_]]">
+        </settings-dropdown-menu>
+      </div>
+    </div>
+  </template>
+  <script src="switch_access_subpage.js"></script>
+</dom-module>

chrome/browser/resources/settings/a11y_page/switch_access_subpage.js

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * Available switch assignment values.
+ * @enum {number}
+ * @const
+ */
+const SwitchAccessAssignmentValue = {
+  NONE: 0,
+  SPACE: 1,
+  ENTER: 2,
+};
+
+/**
+ * @fileoverview 'switch-access-subpage' is the collapsible section containing
+ * Switch Access settings.
+ */
+Polymer({
+  is: 'settings-switch-access-subpage',
+
+  behaviors: [I18nBehavior],
+
+  properties: {
+    /**
+     * Preferences state.
+     */
+    prefs: {
+      type: Object,
+      notify: true,
+    },
+
+    /** @private {Array<number>} */
+    autoScanSpeedValuesMs_: {
+      readOnly: true,
+      type: Array,
+      value: [
+        500,  600,  700,  800,  900,  1000, 1100, 1200, 1300,
+        1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200,
+        2300, 2400, 2500, 2600, 2700, 2800, 2900, 3000, 3100,
+        3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, 4000
+      ]
+    },
+
+    /** @private {Object} */
+    formatter_: {
+      type: Object,
+      value: function() {
+        // navigator.language actually returns a locale, not just a language.
+        const locale = window.navigator.language;
+        const options = {minimumFractionDigits: 1, maximumFractionDigits: 1};
+        return new Intl.NumberFormat(locale, options);
+      },
+    },
+
+    /** @private {number} */
+    maxScanSpeedMs_: {readOnly: true, type: Number, value: 4000},
+
+    /** @private {string} */
+    maxScanSpeedLabelSec_: {
+      readOnly: true,
+      type: String,
+      value: function() {
+        return this.scanSpeedStringInSec_(this.maxScanSpeedMs_);
+      },
+    },
+
+    /** @private {number} */
+    minScanSpeedMs_: {readOnly: true, type: Number, value: 500},
+
+    /** @private {string} */
+    minScanSpeedLabelSec_: {
+      readOnly: true,
+      type: String,
+      value: function() {
+        return this.scanSpeedStringInSec_(this.minScanSpeedMs_);
+      },
+    },
+
+    /** @private {Array<Object>} */
+    switchAssignOptions_: {
+      readOnly: true,
+      type: Array,
+      value: function() {
+        return [
+          {
+            value: SwitchAccessAssignmentValue.NONE,
+            name: this.i18n('switchAssignOptionNone')
+          },
+          {
+            value: SwitchAccessAssignmentValue.SPACE,
+            name: this.i18n('switchAssignOptionSpace')
+          },
+          {
+            value: SwitchAccessAssignmentValue.ENTER,
+            name: this.i18n('switchAssignOptionEnter')
+          },
+        ];
+      },
+    },
+  },
+
+  /**
+   * @return {string}
+   * @private
+   */
+  currentSpeed_: function() {
+    const speed = this.get('prefs.switch_access.auto_scan.speed_ms.value');
+    if (typeof speed != 'number') {
+      return '';
+    }
+    return this.scanSpeedStringInSec_(speed);
+  },
+
+  /**
+   * @return {string} label for the speed slider.
+   * @private
+   */
+  getLabelForSpeedSlider_: function() {
+    const speedString = this.currentSpeed_();
+    return this.i18n('switchAccessAutoScanSpeedLabel', speedString);
+  },
+
+  /**
+   * @param {string} command
+   */
+  onSwitchAssigned_: function(command) {
+    const pref = 'prefs.switch_access.' + command;
+    const keyCodeSuffix = '.key_codes.value';
+    const settingSuffix = '.setting.value';
+
+    switch (this.get(pref + settingSuffix)) {
+      case SwitchAccessAssignmentValue.NONE:
+        this.set(pref + keyCodeSuffix, []);
+        break;
+      case SwitchAccessAssignmentValue.SPACE:
+        this.set(pref + keyCodeSuffix, [32]);
+        break;
+      case SwitchAccessAssignmentValue.ENTER:
+        this.set(pref + keyCodeSuffix, [13]);
+        break;
+    }
+  },
+
+  onNextAssigned_: function() {
+    this.onSwitchAssigned_('next');
+  },
+
+  onPreviousAssigned_: function() {
+    this.onSwitchAssigned_('previous');
+  },
+
+  onSelectAssigned_: function() {
+    this.onSwitchAssigned_('select');
+  },
+
+  /**
+   * @param {number} scanSpeedValueMs
+   * @return {string} a string representing the scan speed in seconds.
+   * @private
+   */
+  scanSpeedStringInSec_: function(scanSpeedValueMs) {
+    const scanSpeedValueSec = scanSpeedValueMs / 1000;
+    return this.i18n(
+        'durationInSeconds', this.formatter_.format(scanSpeedValueSec));
+  },
+});

chrome/browser/resources/settings/chromeos/os_a11y_page/BUILD.gn

@@ -9,6 +9,7 @@ js_type_check("closure_compile") {
     ":os_a11y_page",
     "../../a11y_page:externs",
     "../../a11y_page:manage_a11y_page",
+    "../../a11y_page:switch_access_subpage",
     "../../a11y_page:tts_subpage",
   ]
 }

chrome/browser/resources/settings/chromeos/os_a11y_page/os_a11y_page.html

@@ -8,6 +8,7 @@
 <link rel="import" href="../../controls/settings_toggle_button.html">
 <link rel="import" href="../../settings_page/settings_animated_pages.html">
 <link rel="import" href="../../settings_page/settings_subpage.html">
+<link rel="import" href="../../a11y_page/switch_access_subpage.html">
 <link rel="import" href="../../a11y_page/tts_subpage.html">
 
 <dom-module id="os-settings-a11y-page">
@@ -51,6 +52,15 @@
           </settings-tts-subpage>
         </settings-subpage>
       </template>
+      <template is="dom-if" if="[[showExperimentalSwitchAccess_]]">
+        <template is="dom-if" route-path="/manageAccessibility/switchAccess">
+          <settings-subpage associated-control="[[$$('#subpage-trigger')]]"
+              page-title="$i18n{manageSwitchAccessSettings}">
+            <settings-switch-access-subpage prefs="{{prefs.settings.a11y}}">
+            </settings-switch-access-subpage>
+          </settings-subpage>
+        </template>
+      </template>
     </settings-animated-pages>
   </template>
   <script src="os_a11y_page.js"></script>

chrome/browser/resources/settings/chromeos/os_a11y_page/os_a11y_page.js

@@ -60,6 +60,18 @@ Polymer({
         return loadTimeData.getBoolean('showExperimentalA11yFeatures');
       },
     },
+
+    /**
+     * Whether to show Switch Access.
+     * @private {boolean}
+     */
+    showExperimentalSwitchAccess_: {
+      type: Boolean,
+      value: function() {
+        return loadTimeData.getBoolean(
+            'showExperimentalAccessibilitySwitchAccess');
+      },
+    },
   },
 
   /** @override */

chrome/browser/resources/settings/os_settings_resources.grd

@@ -27,6 +27,12 @@
       <structure name="IDR_OS_SETTINGS_MANAGE_A11Y_PAGE_HTML"
                  file="a11y_page/manage_a11y_page.html"
                  type="chrome_html" />
+      <structure name="IDS_OS_SETTINGS_SWITCH_ACCESS_SUBPAGE_JS"
+                 file="a11y_page/switch_access_subpage.js"
+                 type="chrome_html" />
+      <structure name="IDR_OS_SETTINGS_SWITCH_ACCESS_SUBPAGE_HTML"
+                 file="a11y_page/switch_access_subpage.html"
+                 type="chrome_html" />
       <structure name="IDR_OS_SETTINGS_TTS_SUBPAGE_JS"
                  file="a11y_page/tts_subpage.js"
                  type="chrome_html" />

chrome/browser/resources/settings/route.js

@@ -56,6 +56,7 @@
  *   LOCK_SCREEN: (undefined|!settings.Route),
  *   MANAGE_ACCESSIBILITY: (undefined|!settings.Route),
  *   MANAGE_PROFILE: (undefined|!settings.Route),
+ *   MANAGE_SWITCH_ACCESS_SETTINGS: (undefined|!settings.Route),
  *   MANAGE_TTS_SETTINGS: (undefined|!settings.Route),
  *   MULTIDEVICE: (undefined|!settings.Route),
  *   MULTIDEVICE_FEATURES: (undefined|!settings.Route),
@@ -456,6 +457,8 @@ cr.define('settings', function() {
       // <if expr="chromeos">
       r.MANAGE_ACCESSIBILITY =
           r.ACCESSIBILITY.createChild('/manageAccessibility');
+      r.MANAGE_SWITCH_ACCESS_SETTINGS = r.MANAGE_ACCESSIBILITY.createChild(
+          '/manageAccessibility/switchAccess');
       r.MANAGE_TTS_SETTINGS =
           r.MANAGE_ACCESSIBILITY.createChild('/manageAccessibility/tts');
       // </if>

chrome/browser/resources/settings/settings_resources.grd

@@ -28,6 +28,12 @@
         <structure name="IDR_SETTINGS_MANAGE_A11Y_PAGE_HTML"
                    file="a11y_page/manage_a11y_page.html"
                    type="chrome_html" />
+        <structure name="IDR_SETTINGS_SWITCH_ACCESS_SUBPAGE_JS"
+                   file="a11y_page/switch_access_subpage.js"
+                   type="chrome_html" />
+        <structure name="IDR_SETTINGS_SWITCH_ACCESS_SUBPAGE_HTML"
+                   file="a11y_page/switch_access_subpage.html"
+                   type="chrome_html" />
         <structure name="IDR_SETTINGS_TTS_SUBPAGE_JS"
                    file="a11y_page/tts_subpage.js"
                    type="chrome_html" />

chrome/browser/ui/webui/settings/settings_localized_strings_provider.cc

@@ -265,6 +265,20 @@ void AddA11yStrings(content::WebUIDataSource* html_source) {
     {"switchAccessLabel", IDS_SETTINGS_ACCESSIBILITY_SWITCH_ACCESS_DESCRIPTION},
     {"switchAccessOptionsLabel",
      IDS_SETTINGS_ACCESSIBILITY_SWITCH_ACCESS_OPTIONS_LABEL},
+    {"manageSwitchAccessSettings", IDS_SETTINGS_MANAGE_SWITCH_ACCESS_SETTINGS},
+    {"switchAssignmentHeading", IDS_SETTINGS_SWITCH_ASSIGNMENT_HEADING},
+    {"switchAssignOptionNone", IDS_SETTINGS_SWITCH_ASSIGN_OPTION_NONE},
+    {"switchAssignOptionSpace", IDS_SETTINGS_SWITCH_ASSIGN_OPTION_SPACE},
+    {"switchAssignOptionEnter", IDS_SETTINGS_SWITCH_ASSIGN_OPTION_ENTER},
+    {"assignSelectSwitchLabel", IDS_SETTINGS_ASSIGN_SELECT_SWITCH_LABEL},
+    {"assignNextSwitchLabel", IDS_SETTINGS_ASSIGN_NEXT_SWITCH_LABEL},
+    {"assignPreviousSwitchLabel", IDS_SETTINGS_ASSIGN_PREVIOUS_SWITCH_LABEL},
+    {"switchAccessAutoScanHeading",
+     IDS_SETTINGS_SWITCH_ACCESS_AUTO_SCAN_HEADING},
+    {"switchAccessAutoScanLabel", IDS_SETTINGS_SWITCH_ACCESS_AUTO_SCAN_LABEL},
+    {"switchAccessAutoScanSpeedLabel",
+     IDS_SETTINGS_SWITCH_ACCESS_AUTO_SCAN_SPEED_LABEL},
+    {"durationInSeconds", IDS_SETTINGS_DURATION_IN_SECONDS},
     {"manageAccessibilityFeatures",
      IDS_SETTINGS_ACCESSIBILITY_MANAGE_ACCESSIBILITY_FEATURES},
     {"textToSpeechHeading", IDS_SETTINGS_ACCESSIBILITY_TEXT_TO_SPEECH_HEADING},